Deployment of quickstart template "docker-kibana-elasticsearch" fails.

[docker-kibana-elasticsearch](https://raw.githubusercontent.com/Azure/azure-quickstart-templates/master/docker-kibana-elasticsearch/azuredeploy.json)

### Issue Details
Deployment to Azure fails with the following STATUSMESSAGE:
```
{
"error": {
"code": "ImageNotFound",
"target": "imageReference",
"message": "The platform image 'Canonical:UbuntuServer:15.10:latest' is not available. Verify that all fields in the storage profile are correct."
}
}
```
Looks like it wants to use an old version of Ubuntu.

Open docker-kibana-elasticsearch/azuredeploy.json and inspect the imageReference used by the deployment. Confirm which Ubuntu image version is configured, then update it to an available version and deploy the template to verify that the ImageNotFound error is resolved.

Written by the indexing model from the issue text.